THÔNG TIN TÀI LIỆU
MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY NGUYEN THE TIEN SYNTHESIZE AND INVESTIGATE THE CATALYTIC ACTIVITY OF THREE-WAY CATALYSTS BASED ON MIXED METAL OXIDES FOR THE TREATMENT OF EXHAUST GASES FROM INTERNAL COMBUSTION ENGINE CHEMICAL ENGINEERING DISSERTATION HANOI-2014 e MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY NGUYEN THE TIEN SYNTHESIZE AND INVESTIGATE THE CATALYTIC ACTIVITY OF THREE-WAY CATALYSTS BASED ON MIXED METAL OXIDES FOR THE TREATMENT OF EXHAUST GASES FROM INTERNAL COMBUSTION ENGINE Speciality: Chemical Engineering Code: 62520301 CHEMICAL ENGINEERING DISSERTATION SUPERVISOR: ASSOCIATE PROFESSOR, DOCTOR LE MINH THANG HANOI-2014 e Synthesize and investigate the catalytic activity of three-way catalysts based on mixed metal oxides for the treatment of exhaust gases from internal combustion engine ACKNOWLEDGEMENTS This PhD thesis has been carried out at the Laboratory of Environmental Friendly Material and Technologies, Advance Institute of Science and Technology, Department of Organic and Petrochemical Technology, Laboratory of the Petrochemical Refinering and Catalytic Materials, School of Chemical Engineering, Hanoi University of Science and Technology (Vietnam) and Department of Inorganic and Physical Chemistry, Ghent University (Belgium) The work has been completed under supervision of Associate Prof Dr Le Minh Thang Firstly, I would like to thank Associate Prof Dr Le Minh Thang She helped me a lot in the scientific work with her thorough guidance, her encouragement and kind help I want to thank all teachers of Department of Organic and Petrochemical Technology and the technicians of Laboratory of Petrochemistry and Catalysis Material, Institute of Chemical Engineering for their guidance, and their helps in my work I want to thank Prof Isabel and all staff in Department of Inorganic and Physical Chemistry, Ghent University for their kind help and friendly attitude when I lived and studied in Ghent I gratefully acknowledge the receipt of grants from VLIR (Project ZEIN2009PR367) which enabled the research team to carry out this work I acknowledge to all members in my research group for their friendly attitude and their assistances Finally, I want to thank my family for their love and encouragement during the whole period Nguyen The Tien September 2013 Nguyen The Tien e Synthesize and investigate the catalytic activity of three-way catalysts based on mixed metal oxides for the treatment of exhaust gases from internal combustion engine COMMITMENT I assure that this is my own research All the data and results in the thesis are completely true, was agreed to use in this paper by co-author This research hasn’t been published by other authors than me Nguyen The Tien Nguyen The Tien e Synthesize and investigate the catalytic activity of three-way catalysts based on mixed metal oxides for the treatment of exhaust gases from internal combustion engine CONTENT OF THESIS LIST OF TABLES LIST OF FIGURES INTRODUCTION LITERATURE REVIEW 1.1 10 11 Air pollution and air pollutants 11 1.1.1 Air pollution from exhaust gases of internal combustion engine in Vietnam 11 1.1.2 Air pollutants 11 1.1.2.1 Carbon monoxide (CO) 11 1.1.2.2 Volatile organic compounds (VOCs) 11 1.1.2.3 Nitrous oxides (NOx) 12 1.1.2.4 Some other pollutants 12 1.1.3 Composition of exhaust gas 13 1.2 Treatments of air pollution 1.2.1 Separated treatment of pollutants 1.2.1.1 CO treatments 1.2.1.2 VOCs treatments 1.2.1.3 NOx treatments 1.2.1.4 Soot treatment 1.2.2 Simultaneous treatments of three pollutants 1.2.2.1 Two successive converters 1.2.2.2 Three-way catalytic (TWC) systems 1.3 Catalyts for the exhaust gas treatment 1.3.1 Catalytic systems based on noble metals (NMs) 1.3.2 Catalytic systems based on perovskite 1.3.3 Catalytic systems based on metallic oxides 1.3.3.1 Metallic oxides based on CeO2 1.3.3.2 Catalytic systems based on MnO2 1.3.3.3 Catalytic systems based on cobalt oxides 1.3.3.4 Other metallic oxides 1.3.4 Other catalytic systems 1.4 Mechanism of the reactions 1.4.1 1.4.2 1.4.3 1.4.4 1.5 Aims of the thesis 2.2 20 21 23 23 24 25 26 27 28 37 37 Sol-gel synthesis of mixed catalysts Catalysts supported on γ-Al2O3 Aging process Physico-Chemistry Experiment Techniques 2.2.1 19 35 Synthesis of the catalysts 2.1.1 2.1.2 2.1.3 14 14 14 14 15 16 17 17 Mechanism of hydrocarbon oxidation over transition metal oxides 28 Mechanism of the oxidation reaction of carbon monoxide 29 Mechanism of the reduction of NOx 31 Reaction mechanism of three-way catalysts 33 EXPERIMENTAL 2.1 14 X-ray Diffraction 37 37 38 38 38 Nguyen The Tien e Synthesize and investigate the catalytic activity of three-way catalysts based on mixed metal oxides for the treatment of exhaust gases from internal combustion engine 2.2.2 Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) 2.2.3 BET method for the determination of surface area 2.2.4 X-ray Photoelectron Spectroscopy (XPS) 2.2.5 Thermal Analysis 2.2.6 Infrared Spectroscopy 2.2.7 Temperature Programmed Techniques 2.3 Catalytic test 43 2.3.1 Micro reactor setup 2.3.2 The analysis of the reactants and products 2.3.2.1 Hydrocarbon oxidation 2.3.2.2 CO oxidation 2.3.2.3 Soot treatment 2.3.2.4 Three -pollutant treatment RESULTS AND DISCUSSIONS 3.1 40 40 40 41 41 42 Selection of components for the three-way catalysts 43 44 45 47 47 47 48 48 3.1.1 Study the complete oxidation of hydrocarbon 48 3.1.1.1 Single and bi-metallic oxide 48 3.1.1.2 Triple metallic oxides 51 3.1.2 Study the complete oxidation of CO 53 3.1.2.1 Catalysts based on single and bi-metallic oxide 53 3.1.2.2 Triple oxide catalysts MnCoCe 54 3.1.2.3 Influence of MnO2, Co3O4, CeO2 content on catalytic activity of MnCoCe catalyst 59 3.1.3 Study the oxidation of soot 62 3.2 MnO2-Co3O4-CeO2 based catalysts for the simultaneous treatment of pollutants 66 3.2.1 MnO2-Co3O4-CeO2 catalysts with MnO2/Co3O4=1/3 66 3.2.2 MnO2-Co3O4-CeO2 with the other MnO2/Co3O4 ratio 68 3.2.3 Influence of different reaction conditions on the activity of MnCoCe 1-3-0.75 69 3.2.4 Activity for the treatment of soot and the influence of soot on activity of MnCoCe 1-3-0.75 72 3.2.5 Influence of aging condition on activity of MnCoCe catalysts 74 3.2.5.1 The influence of steam at high temperature 74 3.2.5.2 The characterization and catalytic activity of MnCoCe 1-3-0.75 in different aging conditions 77 3.2.6 Activity of MnCoCe 1-3-0.75 at room temperature 80 3.3 Study on the improvement of NOx treatment of MnO2Co3O4-CeO2 catalyst by addition of BaO and WO3 81 3.4 Study on the improvement of the activity of MnO2-Co3O4CeO2 catalyst after aging by addition of ZrO2 84 3.5 Comparison between MnO2-Co3O4-CeO2 catalyst and noble catalyst 87 CONCLUSIONS REFERENCES LIST OF PUBLISHMENTS 91 92 100 Nguyen The Tien e Synthesize and investigate the catalytic activity of three-way catalysts based on mixed metal oxides for the treatment of exhaust gases from internal combustion engine ABBREVIATION TWCs: Three-Way Catalysts NOx: Nitrous Oxides VOCs: Volatile Organic Compounds PM10: Particulate Matter less than 10 nm in diameter NMVOCs: Non-Methane Volatile Organic Compounds HC: hydrocarbon A/F ratio: Air/Fuel ratio λ: the theoretical stoichiometric value, defined as ratio of actual A/F to stoichiometric; λ can be calculated λ= (2O2+NO)/ (10C3H8+CO); λ = at stoichiometry (A/F = 14.7) SOF: Soluble Organic Fraction DPM: Diesel Particulate Matter CRT: Continuously Regenerating Trap NM: Noble Metal Cpsi: Cell Per Inch Square In.: inch CZ (Ce-Zr): mixtures of CeO2 and ZrO2 CZALa: mixtures of CeO2, ZrO2, Al2O3, La2O3 NGVs: natural gas vehicles OSC: oxygen storage capacity WGS: water gas shift LNTs: Lean NOx traps NSR: NOx storage-reduction SCR: selective catalytic reduction SG: sol-gel MC: mechanical FTIR: Fourier-Transform Infrared Eq.: equation T100: the temperature that correspond to the pollutant was completely treatment Tmax: The maxium peak temperature was presented as reference temperature of the maximum reaction rate in TG-DTA (DSC) diagram Vol.: volume Wt : weight Cat: catalyst at: atomic min.: minutes h: hour Nguyen The Tien e luan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trong Synthesize and investigate the catalytic activity of three-way catalysts based on mixed metal oxides for the treatment of exhaust gases from internal combustion engine LIST OF TABLES Table 1.1 Example of exhaust conditions for two- and four-stroke, diesel and lean-four-stroke engines [67] .13 Table 1.2 Adsorption/desorption reactions on Pt catalyst [101] 34 Table 1.3 Surface reactions of propylene oxidation [101] 34 Table 1.4 Surface reactions of CO oxidation [101] .35 Table 1.5 Surface reactions of hydroxyl spices, NO and NO2 [101] 35 Table 2.1 Aging conditions of MnCoCe catalysts 38 Table 2.2 Strong line of some metallic oxides .39 Table 2.3 Binding energy of some atoms [102] 41 Table 2.4 Specific wave number of some function group or compounds 42 Table 2.5 Composition of mixture gases at different reaction conditions for C3H6 oxidation 43 Table 2.6 Composition of mixture gases at different reaction conditions for CO oxidation 44 Table 2.7 Composition of mixture gases at different reaction conditions for treatment of CO, C 3H6, NO .44 Table 2.8 Temperature Program of analysis method for the detection of reactants and products 45 Table 2.9 Retention time of some chemicals 45 Table 3.1 Quantity of hydrogen consumed volume (ml/g) at different reduction peaks in TPR-H2 profiles of pure CeO2, Co3O4, MnO2 and CeO2-Co3O4, MnO2-Co3O4 chemical mixtures .51 Table 3.2 Consumed hydrogen volume (ml/g) of the mixture MnO2-Co3O4-CeO2 1-3-0.75 55 Table 3.3 Adsorbed oxygen volume (ml/g) of some pure single oxides (MnO2, Co3O4, CeO2) and chemical mixed oxides MnCoCe 1-3-0.75 56 Table 3.4 Surface atomic composition of the sol-gel and mechanical sample 59 Table 3.5 Tmax of mixture of single oxides and soot in TG-DTA (DSC) diagrams .63 Table 3.6 Catalytic activity of single oxides for soot treatment .63 Table 3.7 Tmax of mixture of multiple oxides and soot determined from TG-DTA diagrams 65 Table 3.8 Catalytic activity of multiple oxides for soot treatment at 500oC 65 Table 3.9 Soot conversion of some mixture of MnCoCe 1-3-0.75 and soot in the flow containing CO: 4.35%, O2: 7.06%, C3H6: 1.15%, NO: 1.77% at 500oC for 425 .72 Table 3.10 Specific surface area of MnCoCe catalysts before and after aging in the flow containing 57% vol.H2O at 800oC for 24h .76 Table 3.11 Consumed hydrogen volume (ml/g) of the MnCoCe 1-3-0.75 fresh and aging at 800oC in flow containing 57% steam for 24h 77 Table 3.12 Specific surface area of MnCoCe 1-3-0.75 fresh and after aging in different conditions 79 Table 3.13 Specific surface area of catalysts containing MnO2, Co3O4, CeO2, BaO and WO3 81 Table 3.14 Specific surface area of some catalyst containing MnO2, Co3O4, CeO2, ZrO2 before and after aging at 800oC in flow containing 57% steam for 24h 85 Table 3.15 Specific surface area of noble catalyst and metallic oxide catalysts supported on γAl2O3 87 Nguyen The Tien luan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trong e luan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trong Synthesize and investigate the catalytic activity of three-way catalysts based on mixed metal oxides for the treatment of exhaust gases from internal combustion engine LIST OF FIGURES Figure 1.1 Micrograph of diesel soot, showing particles consisting of clumps of spherules [110] 13 Figure 1.2 A typical arrangement for abatement of NOx from a heavy-duty diesel engine using urea as reducing agent [67] 15 Figure 1.3 Principle of filter operation (1) and filter re-generation (2) for a soot removal system, using fuel powered burners [67] 16 Figure 1.4 The working principle of the continuously regenerating particulate trap [67] 16 Figure 1.5 Scheme of successive two-converter model [1] 17 Figure 1.6 Three- way catalyst performance determined by engine air to fuel ratio [43] 18 Figure 1.7 Diagram of a modern TWC/engine/oxygen sensor control loop for engine 18 Figure 1.8 Wash-coats on automotive catalyst can have different surface structures as shown with SEM micrographs [43] 19 Figure 1.9 Improvement trend of catalytic converter [43] 19 Figure 1.10 Scheme of catalytic hydrocarbon oxidation; H-hydrocarbon, C-catalyst, R1 to R5-labile intermediate, probably of the peroxide type [97] 29 Figure 1.11 Reaction cycle and potential energy diagram for the catalytic oxidation of CO by O2 [98] .30 Figure 1.12 Reaction pathways of CO oxidation over the metallic oxides [34] .31 Figure 1.13 Chemical reaction pathways of selective catalytic reduction of NOx by propane [99] 32 Figure 1.14 Principle of operation of an NSR catalyst: NOx are stored under oxidising conditions (1) and then reduced on a TWC when the A/F is temporarily switched to rich conditions (2) [67].33 Figure 1.15 Schematic representation of the seven main steps involved in the conversion of the exhaust gas pollutants in a channel of a TWC [100] 33 Figure 2.1 Aging process of the catalyst (1: air pump; 2,6: tube furnace, 3: water tank, 4: heater, 5,7: screen controller, V1,V2: gas valve) 38 Figure 2.2 Micro reactor set up for measurement of catalytic activity 43 Figure 2.3 The relationship between concentration of C3H6 and peak area 46 Figure 2.4 The relationship between concentration of CO2 and peak area 46 Figure 2.5 The relationship between concentration of CO and peak area 47 Figure 3.1 Catalytic activity of some mixed oxide MnCo, CoCe and single metallic oxide in deficient oxygen condition 49 Figure 3.2 Catalytic activity of MnCo 1-3 and CeCo 1-4 catalysts in excess oxygen condition 49 Figure 3.3 C3H6 conversion of CeCo1-4 in different reaction conditions (condition a: excess oxygen condition with the presence of CO: 0.9 %C3H6, 0.3%CO, 5%O2, N2 balance, condition b: excess oxygen condition with the presence of CO and H2O: 0.9 %C3H6, 0.3 %CO, 2% H2O, %O2, N2 balance) 50 Figure 3.4 XRD patterns of CeCo=1-4, MnCo=1-3 chemical mixtures and some pure single oxides 50 Figure 3.5 Conversion of C3H6, C3H8 and C6H6 on MnCoCe 1-3-0.75 catalyst under sufficient oxygen condition 52 Figure 3.6 SEM images of MnCo 1-3 fresh (a),MnCoCe 1-3-0.75 before (a) and after (b) reaction under sufficient oxygen condition (O2/C3H8=5/1) 52 Figure 3.7 XRD pattern of MnCoCe 1-3-0.75 and original oxides 53 Figure 3.8 CO conversion of some catalysts in sufficient oxygen condition 53 Figure 3.9 SEM images of MnCo=1-3 before (a) and after (b) reaction under sufficient oxygen condition 54 Figure 3.10 CO conversion of original oxides (MnO2, Co3O4, CeO2) and mixtures of these oxides in excess oxygen condition (O2/CO=1.6) 55 Figure 3.11 TPR H2 profiles of the mixture MnCoCe 1-3-0.75, MnCo 1-3 and pure MnO2, Co3O4, CeO2 samples .56 Figure 3.12 IR spectra of some catalyst ((1): CeO2; (2): Co3O4; (3): MnO2; (4): MnCo 1-3; (5):MnCoCe 1-3-0.75 (MC); (6): MnCoCe 1-3-0.75 (SG)) 57 Nguyen The Tien luan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trong e luan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trong Synthesize and investigate the catalytic activity of three-way catalysts based on mixed metal oxides for the treatment of exhaust gases from internal combustion engine Figure 3.13 XRD pattern of MnCoCe 1-3-0.75 synthesized by sol-gel and mechanical mixing method .57 Figure 3.14 XPS measurement of Co 2p region (a), Ce 3d region (b), Mn 2p region (c) and O 1s region (d) of the mechanical mixture (1) and chemical MnCoCe 1-3-0.75 sample (2) 58 Figure 3.15 XRD patterns of MnO2-Co3O4-CeO2 samples with MnO2-Co3O4=1-3(MnCoCe 1-30.17 (a), MnCoCe 1-3-0.38 (b), MnCoCe 1-3-0.75 (c), MnCoCe 1-3-1.26 (d); MnCoCe 1-3-1.88 (e) 60 Figure 3.16 XRD patterns of MnO2-Co3O4-CeO2 samples with MnO2-Co3O4=7-3: MnCoCe 7-34.29 (a), MnCoCe 7-3-2.5 (b) and MnCo=7-3 (c) .60 Figure 3.17 Specific surface area of MnCoCe catalysts with different MnO2/Co3O4 ratios 61 Figure 3.18 Temperature to reach 100% CO conversion (T100) of mixed MnO2-Co3O4-CeO2 samples with the molar ratio of MnO2-Co3O4 of 1-3 (a) and MnO2-Co3O4=7-3 (b) with different CeO2 contents 61 Figure 3.19 TG-DSC and TG-DTA of soot (a), mixture of soot-Co3O4 (b), soot-MnO2 (c), sootV2O5 (d) with the weight ratio of soot-catalyst of 1-1 62 Figure 3.20 XRD patterns of MnCoCe 1-3-0.75 (1), MnCoCeV 1-3-0.75-0.53 (2), MnCoCeV 1-30.75-3.17 (3) 64 Figure 3.21 TG-DTA of mixtures of soot and catalyst (a: MnCoCe 1-3-0.75, b: MnCoCeV 1-30.75-1.19, c: MnCoCeV 1-3-0.75-3.17, d: MnCoCeV 1-3-0.75-42.9) 64 Figure 3.22 Catalytic activity of MnCoCeV 1-3-0.75- 3.17 in the gas flow containing 4.35% CO, 7.06% O2, 1.15% C3H6 and 1.77% NO 65 Figure 3.23 C3H6 and CO conversion of MnCoCe catalyst with MnO2/Co3O4=1-3 (flow containing 4.35% CO, 7.65% O2, 1.15% C3H6 and 0.59% NO) 66 Figure 3.24 Catalytic activity of MnCoCe catalyst with MnO2-Co3O4 =1-3 (flow containing 4.35% CO, 7.06% O2, 1.15% C3H6, 1.77% NO) 67 Figure 3.25 SEM images of MnCoCe 1-3-0.75 (a), MnCoCe 1-3-1.26 (b), MnCoCe 1-3-1.88 (c).68 Figure 3.26 Catalytic activity of MnCoCe catalysts with ratio MnO2-Co3O4=7-3(flow containing 4.35% CO, 7.06% O2, 1.15% C3H6 and 1.77% NO) 69 Figure 3.27 Catalytic activity of MnCoCe 1-3-0.75 with different lambda values 70 Figure 3.28 CO and C3H6 conversion of MnCoCe 1-3-0.75 in different condition (non-CO2 and 6.2% CO2) 71 Figure 3.29 Catalytic activity of MnCoCe 1-3-0.75 at high temperatures in 4.35% CO, 7.65% O2, 1.15% C3H6, 0.59 % NO 71 Figure 3.30 Catalytic activity of MnCoCe 1-3-0.75 with the different mass ratio of catalytic/soot (a: C3H6 conversion, b: NO conversion, c: CO2 concentration in outlet flow; d: CO concentration in outlet flow) at 500oC 73 Figure 3.31 Catalytic activity of MnCoCe (MnO2-Co3O4 =1-3) catalysts before and after aging at 800oC in flow containing 57% steam for 24h 74 Figure 3.32 XRD patterns of MnCoCe catalysts before and after aging in a flow containing 57% vol.H2O at 800oC for 24h (M1: MnCoCe 1-3-0.75 fresh, M2: MnCoCe 1-3-0.75 aging, M3: MnCoCe 1-3-1.88 fresh, M4: MnCoCe 1-3-1.88 aging), Ce: CeO2, Co:Co3O4 75 Figure 3.33 SEM images of MnCoCe catalysts before and after aging at 800oC in flow containing 57% steam for 24h (a,d: MnCoCe 1-3-0.75 fresh and aging, b,e: MnCoCe 1-3-.26 fresh and aging, c,f: MnCoCe 1-3-1.88 fresh and aging, respectively) 76 Figure 3.34 TPR-H2 pattern of MnCoCe 1-3-0.75 fresh and aging at 800oC in flow containing 57% steam for 24h .77 Figure 3.35 Catalytic activity of MnCoCe 1-3-0.75 fresh and after aging in different conditions 78 Figure 3.36 XRD pattern of MnCoCe 1-3-0.75 in different aging conditions .79 Figure 3.37 SEM images of MnCoCe 1-3-0.75 fresh and after aging in different conditions 80 Figure 3.38 Activity of MnCoCe 1-3-0.75 after activation 80 Figure 3.39 CO and C3H6 conversion of MnCoCe 1-3-0.75 at room temperature after activation 2h in gas flow 4.35% CO, 7.65% O2, 1.15% C3H6, 0.59% NO with and without CO2 81 Figure 3.40 XRD pattern of catalysts based on MnO2, Co3O4, CeO2, BaO and WO3 .82 Nguyen The Tien luan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trongluan.van.thac.si.tong.hop.va.nghien.cuu.hoat.tinh.cua.xuc.tac.ba.chuc.nang.tren.co.so.hon.hop.oxit.kim.loai.de.xu.ly.khi.thai.dong.co.dot.trong e
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